The present invention relates to a pump device and method for removing a liquid from a container and dispensing it in the form of a spray.
More specifically, the present invention relates to a device of the type having a pump attached to the upper end of the container. The pump includes a pump body disposed in the container and a piston is movable in the pump body and provided with a hollow rod projecting outside of the pump. A cylindrical cap is attachable to the container and has a pivotable actuating and dispensing element provided with a dispensing nozzle communicating via a passage with a cylindrical sheath projecting inside the actuating element. The free end of the hollow rod of the pump piston engages the cylindrical sheath.
The actuating element includes at a first end a lever and at a second end a spray nozzle. The actuating element is articulated to the cap, the cap being hollowed to provide access to the opposite end of the lever-shaped actuating element, the first end also providing a bearing area for the user's finger. When the user presses down, the actuating element pivots, exerting a downward force on the hollow rod of the piston engaged by its free end in the internal cylindrical sheath of the actuating element.
The hollow rod constitutes means or structure by which the pumped liquid passes from the container to the dispensing nozzle of the cap. The axial movement of the hollow rod of the piston must be substantially if not fully linear, also keeping in mind that sufficient rigidity on the rod must be maintained to prevent any buckling as the rod moves when the actuating element pivots.
A number of solutions have been proposed to take into account off-center forces applied to the rigid hollow rod of the pump piston as a result of the pivoting movement of the actuating element.
For example, FR-A-2,682,937 proposes to connect the end of the hollow piston rod to the cylindrical sheath of the actuating element by a tubular element with flexible links. This solution requires separate fabrication of an additional built-on part to link the hollow piston rod to the actuating and dispensing element.
Also, the assignee of the present invention has proposed (in French Patent Application No. 94 00988) to manufacture the cylindrical sheath of the actuating and dispensing element in the form of a relatively long flexible passage. In practice, however, the cap and the actuating element provided with the cylindrical sheath and made in one piece therewith must be made of a relatively rigid material, such as polypropylene or high-density polyethylene. Indeed, the cap must be sufficiently rigid so that, on the one hand, it can be snapped onto the container body and, on the other hand, can ensure that the hinge area providing the articulated link of the actuating element to the cap wall is sufficiently strong to allow a large number of actuations, and finally to ensure that the lever-shaped actuating element is sufficiently rigid over its entire length.
If a rigid material is used to make an assembly including the cap and actuating element, the cylindrical sheath of the actuating element, to be sufficiently flexible, must have a very thin wall, which entails the risk of flexural breakage when the actuating element pivots.
The device known from the French patent application referred to above is possible, in practice, only with pumps such as those described in this document, requiring only a short length of travel of the hollow rod of the pump piston, and is accordingly limited in application.